1. Field of the Invention
This invention relates to improvements in form-and-fill packaging machines and particularly to a separator-folder for edges of packaging film used in such machines.
2. Background Art
Form-and-fill packaging machines are well known in the art and are commercially available. They are commonly used for simultaneously forming and filling packages with diverse material including snack foods such as potato chips and the like. In such machines a packaging film is provided in a flat web to a former which in turn guides the flat web into a tubular shape and presents the edges of the tubular web for sealing. Simultaneously, material to be packed in the packages is fed through a funnel into the formed tube. End seals seal the tube transversely at spaced points to provide the separate packages. One example of a form-and-fill machine is shown in expired U.S. Pat. No. 2,899,875, granted Aug. 18, 1959.
Form-and-fill machines include means for providing a longitudinal or back seal in the tube forming the package. This seal can either be a fin seal or an overlapping seal. In a fin seal the two edges of the tubular web have the same surface mating so that the seal extends outwardly like a fin. In an overlapping seal, the opposite surface of opposite edges of the tubular web are made so that the edges overlap. Generally, fin seals are considered advantageous.
In the handling of some packaging film in many form-and-fill machines there is no provision for adapting such machines for fin seal operation. That is, the formers of many known form-and-fill machines position the edges in overlapping fashion for an overlapping back seal.
In the handling of some packaging films with form-and-fill machines there exists a problem due to the coefficient of friction of the film operating where the edges of the film material are in contact and where they are in contact with formers, thus making control of the folding edge of the film difficult if not impossible. If the packaging film is relatively stiff the coefficient of friction usually increases and the control decreases, exascerbating the problem.
It is known in the art to use a separator between the lips of a former cross-over to separate edges of packaging material. However, such known separators do not offer folding control, and may create additional disadvantageous friction effects.
There exists a need in the art to adapt conventional equipment and use packaging materials which cannot function on conventional equipment and to improve the quality of back seals produced on form-and-fill machines.